LAG is created but LACP configuration is not pushed

As documented, LACP config won't be rendered until the CT assignment. Please go through the following documents for details.

"When you form a LAG, it inherits any connectivity templates assigned on the individual links. The LAG is created, but LACP configuration won't be pushed to the device until connectivity templates are applied. When you form a LAG, it inherits any connectivity templates assigned on the individual links."

https://www.juniper.net/documentation/us/en/software/apstra5.1/apstra-user-guide/topics/task/lag-form.html